More than five auxiliary engines such as crankshaft, water pump, fan, air conditioning, power steering pump are equipped with an automobile and as a medium to drive them pulley is used Although the shape of pulley is simple, structure analysis is important when we design a pulley Because if pulleys are equipped in an engine only once, durability should be ensured until a junked car and according to thickness and shape stress of pulleys are affected. So in this study, we suggested optimizating design process and methodology of pulley using structure and fatigue analysis considering decreasing rate of cross section occurring in press process, shape and material thickness of pulley.